Sugarcatmom - thanks for the links I will check them out.
She's not limping just leaning/wobbly abit & sitting *carefully* & laying down more when she used to be sitting. The thing is I know the weakness could be related to not having enough water re CRF, I don't want to assume it is arthritis & ignore the other possiblilities which is why I'm probably too cautious with the water - though (arthritis) that's what it looks like

I see now the sodium is higher than others, so that maybe it.
With EVO I was adding 2 tsp, now with NV & Wellness I'm adding 4 tsp so it's quite gravyish.
What concerns me is the techs always mentioned she was a bit dehydrated {gums are def not tacky feeling} & of course I'd like to stall sub-q as long as possible.
According to some info the techs gave me from RC

Quote:

The recommended water consumption of the cat is 55 - 70 ml/kg-body weight/per day or 1ml per kcal of metabolizable energy consumed

This is where I get
1 tsp=5ml 11 tsp = 55 ml low end of scale 11 tsp * 5.5kg (Duffy's weight) =60.5 tsp water per day
this would be assuming only straight h2o drinking - not including amount in canned food